The ultimate goal of this project is development of the Therapeutic Implant (TI), a novel intralesional drug delivery system. The TI, a viscous injectable gel, is comprised of a protein carrier matrix, vasoactive tissue modifier and therapeutic agent. The TI delivering 5-FU, referred to as 5-FU TI, will be utilized in this study. The applicant will examine the feasibility of utilizing this new technology of site-specific treatment with sustained drug release to provide effective local tumor control to patients with cutaneous manifestations of Kaposi's sarcoma (KS). Twelve patients with histologically-confirmed, indolent cutaneous KS lesions will be treated in an open-label, dose-comparison study evaluating three doses of 5-FU TI and a placebo, administered up to two times to individual lesions in conjunction with a no-treatment control. Patients will be evaluated over six months for safety (local and systemic toxicity) and efficacy (lesion regression and duration of response).